One-to-Many Table Relationships
Posted by jeffhobbs on February 21, 2008
I recently had a conversation with a blog reader via email. I haven’t asked the gentleman’s permission to post his letter, so I won’t use names. However here is what he wrote:
Jeff, I am contacting you because I am frustrated that GeoMedia Pro 6.1 appears to have no way of creating a one-to-many relationship between records in two tables based on a unique identifier without generating more features in the feature table. An example of this would be eg. a tax parcel has more than one deed, each showing the succession of ownership, and by selecting the parcel I would like to see all deeds related to this parcel by selecting this parcel in the map window or from the record in the feature table. I do not want to join the tables because I do not want an overlapping polygon parcel for each deed record.
I have filed a request with Intergraph each year since version 5.2 of GeoMedia Pro requesting some kind of one-to-many relate and they can not tell me how to do it and don’t seem to be interested in adding it to GeoMedia. This can be achieved in MS Access 97 and above and I was using it in ArcView back in 1994 as “linked tables”, and now I use it in ArcMap as the “relate tables” command, but GeoMedia Pro 6.1 appears still to have no way of implementing such a basic database concept.
And here was reply:
I’ve run into that issue before as well. You basically want a parent (polygon) child relationship type of implementation. I don’t believe there’s a way to do that without customization in GM 6.1. Although I don’t have GeoMedia Parcel Manager, I do believe it’s in that product. That maybe the reason why they don’t put it in the core.
Not sure if you’re looking for workarounds, but you could probably do something with hyperlinks and calling a web page or outside application.
For instance, click on a link in the GM properties dialog and that will call a web page that shows the information. Not ideal I realize, but a possible workaround nonetheless.
I then forwarded on the email trail to someone I know at Intergraph. The person would not confirm, but did offer the following feedback to me:
I hear there may be a data modeling initiative involving all three of Intergraph’s SG&I product families, GeoMedia, G-Technology and CAD/Security, that will allow this type of relationship to be defined and used with the next major release of GeoMedia.
So, like any product; until you can see the functionality in the product, don’t rely on it being in the product. However it does look somewhat promising that we’ll see (finally) a way to handle this type of relationship in the GeoMedia core.
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